Membrane electrode assembly incorporating unified encapsulation and electrocoat paint systems incorporating the same

ABSTRACT

A membrane electrode assembly incorporating an encapsulation assembly process that separates the counter-electrode, and the electrocoat medium from contacting the electrode, which is located behind the membrane ion exchange layer. The encapsulation process provides of method of singularly encasing independent components that comprise the membrane electrode assembly, without the assistance of first structures used in enclosure, framing, enclosure sealing or bonding the components in place, individually, and or in groups thereof from the electrocoat medium, while providing an internal chamber within the membrane electrode assembly, for independent fluid circulation. In further embodiments of the invention, electrode membrane cells having an internal fluid routing system, protective guard around the periphery of the encapsulation layer, a membrane support system adjacent to the membrane, a nonconductive barrier, the membrane, the electrode, and membrane inner spacer bonded by the encapsulation material, cells utilizing the encapsulation method of construction and assembly processes providing the final electrode membrane cell assembly.

BACKGROUND OF INVENTION

The present invention relates to membrane electrode cells used inelectro-deposition processes. More particularly, in the embodiments, thepresent invention describes advantages in simultaneously encapsulatingmembrane electrode assemblies wherein layered structural components ofthe electrode membrane cell assembly, including the membrane areintergraded into a single encapsulated bond, creating an assembly of theindividual structures/components of the membrane electrode cell withoutthe need of a first structures-frames to provide the enclosure.

The industry employees two commonly known electro-coating processesAnionic and cationic, both of these processes are still in commercialuse.

Membrane electrode cells are currently commonly used inelectro-deposition systems. The purpose of these cells is to Isolate theelectrode from the paint bath, provide a chamber to contain the internalcirculating fluid, Exchange electrical energy to the paint bath, whileremoving ions during the process.

The membrane electrode cell can have many shapes, most commonly in ordertubular, C semi-circular and flat. Electro deposition processesutilizing such membrane electrode cells are disclosed in U.S. Pat. Nos.4,851,102, 4,711,709 and 4,834,861

The membrane commonly used for this process is ion exchange or neutral.The membrane is arranged in support structures to separate theelectro-coating bath from the electrode. A fluid flows between theinside of the face of the anode and the membrane. This fluid typicallyis comprised of RO or DI water with either a small amount of acid oramines depending on process. The solution is used to flush ions andcontaminants from the inner chamber.

To separate the electrode from the paint bath it is common practice toprovide a seal or bonding of the membrane to another structure member ofthe cell. These seals in the past have been accomplished by mechanicalmeans such as bolted flanges, which provide sealing by compressing aseal between the flange, membrane, and outer membrane housing along theoutside rim of the housing. This method proves difficult to maintain andrepair.

Yet another method commonly used incorporates the membrane bonded to anindependent first structural component using compression-independentsealing, or bonded arrangement, Disclosed in U.S. Pat Application20040231992 The first structural component typically contains anelectrode that is spaced behind the membrane to create a chamber withina first structural component. The electrode can be mechanically fixed toan enclosure or is sealed in a channeled first structure using manycommon commercially practiced methods of bonding to the first structuralmember completing the chamber for the above fluid. A non-conductivecoating is applied to the backside of the electrode to insulate theelectrode. This above process uses multiple bonding processes andmechanical framing to provide the sealed chamber within the cell.Further more the fluid delivery systems typically in either example aresimply attached internally to the first structural member by epoxy atcertain points along the first structure. The membrane and electrodeassembly is dependant on other periphery or first structural members toprovide the chamber, sealing support and integrity to the cell. Thesemethods, though better than the first method still incorporates multipleapplications of bonding material to a frame or structural supportmechanism which increase chances of sealing failure. The necessity ofperiphery structural members adds increased thickness to the cell, andmore resources in which to produce a chambered membrane electrode cell.

Upon reflection of these and other background in the field, thereremains a need for assemblies further simplified in design, whichenables a faster assembly and eliminates excessive bonding requirementsto enclosures and first structures, which in turn provides a membraneelectrode cell with increased usable electrode area and a smallerfootprint in the electro-deposition tank.

SUMMARY OF INVENTION

In light of this, one aspect of the present invention provides amembrane electrode system for electro-deposition of the conductive fluidcoating medium to the counter anode. A system for electro-deposition ofpaint onto a counter electrode, in which the system incorporates anelectro-deposition main tank containing electrically conductive liquidmedium consisting of pigment, resins, water, acids, or other. Furtherincluded at least one membrane electrode assembly in contact with theabove medium. Said membrane and electrode assembly including operationalstructures for the membrane electrode cell encapsulated simultaneouslyto provide, a single medium encasing, a sealed chamber between thecounter-electrode, internal fluid delivery and return system, andelectrical input within said electro-deposition medium, wherein passageof electrical current between said counter-electrode and said membraneelectrode cell through said liquid medium causing electro-deposition ofsaid pigments and resins on to the said counter-electrode. In preferredembodiments, the electrode within the membrane cell is flat orsemi-circular shape, the membrane and other operational structures areencased using encapsulation assembly, relieving necessity of primaryframes, first structures, or bonding components including membrane tosaid structures.

A system for electro-deposition of paint onto a counter electrode, inwhich the system incorporates an electro-deposition tank containingelectrically conductive liquid medium and a membrane electrode assembly.Further included at least one membrane electrode in contact with theabove medium. Said membrane electrode assembly including an electrode,membrane and operational components for separating said electrode fromabove liquid medium. Said membrane and electrode including operationalstructures for the membrane electrode assembly are encapsulatedsimultaneously to provide a continuous single medium bond, to providesealed chamber there between the counter-electrode. In preferredembodiments the encapsulated cell being of box or semi-circular shape isfitted with an edge guard to protect the encapsulation layer.

In the preferred embodiments, the electrode within the membraneelectrode assembly is a flat or semi-circular shape electrode, and theencapsulation process can be generated by non-electro conductive:liquefied polymers, liquefied plastics, Liquid epoxies, Viscous bindingagents, Multi component epoxies, single component adhesives and similar.

Further embodiments, the present invention provides a membrane electrodeassembly for use in electro-deposition system as previously described.The assembly comprises of an encapsulation process, which includesvarious components such as, but not limited to, the electrode, fluidsupply channel, non-conductive sheet, membrane, and membrane supportlayers. In certain embodiments the electrode is flat or semi-circularand the encapsulated membrane electrode assembly is then encased in aperiphery guard for further protection of the assembly.

In another embodiment, the present invention provides a membraneelectrode assembly for use in electro-deposition system as previouslydescribed. The encapsulation process of the components provides therequired space for the chamber that contains the space to circulate andpass internal fluids.

In another embodiment, the present invention provides a membraneelectrode assembly for use in electro-deposition system as previouslydescribed. Wherein a chamber is created internal to the encapsulationmedium between the electrode and membrane, creating a path for theincoming fluid that is used in the circulation of said fluid.

In another embodiment, the present invention provides a membraneelectrode assembly for use in electro-deposition system as previouslydescribed. The internal chamber used for supplying the path for theflushing fluid is incorporated throughout the encapsulation layer.Providing at least one opening to supply the fluid through encapsulationlayer to the chamber. Another embodiment provides at least one openingfor an outlet of the fluid through the encapsulation layer.

In another embodiment, the present invention provides a membraneelectrode assembly for use in electro-deposition system as previouslydescribed. The encapsulation layer provides sealing of the electrodeelectrical connection from the chamber wherein the fluid is circulated.

In another embodiment, the present invention provides a membraneelectrode assembly for use in electro-deposition system as previouslydescribed. The encapsulation process provides one or more layers ofmembrane retaining material. The first of which is an epoxy saturatedwoven blend adjacent to the membrane followed by the second layer ofstructural mesh. The layers provide containment of internal chamberpressure, reducing chamber swelling under pressure.

In another embodiment, the present invention provides a membraneelectrode assembly for use in electro-deposition system as previouslydescribed. The encapsulation process incorporates a transparent sheet ofelectrically insulating material, behind the electrode, electricallysealing the back of the assembly. In another embodiment the transparentsheet is utilized to inspect the electrode for wear.

In another embodiment, the present invention provides a membraneelectrode assembly for use in electro-deposition system as previouslydescribed. During the encapsulation of all the membrane electrodecomponents a periphery guard is attached to protect the edges of theassembly.

Additional features, embodiments and advantages of the invention will beapparent to those of ordinary knowledge in the art derived from thedescriptions herein.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 Provides a perspective view of a preferred membrane electrodecell assembly, of the invention. Viewings of Side, Front and Back

FIG. 2 Provides a partial cut away view (A-A) of the cell assembly ofFIG. 1

FIG. 3 Provides a cross sectional view of the cell assembly of FIG. 1,Taken along line (B-B) and (C-C) and viewed in the correspondingdirection.

DESCRIPTION OF PREFERRED EMBODIMENTS

To promote an understanding of the principles of the invention,reference will be made to certain preferred embodiments, in specificterminology to describe the same. It will be understood that nolimitation of the scope of the invention is thereby intended, suchalterations, further modifications and application principles of theinvention as described herein being disclosed as would normally occur toone skilled in the art to which the invention applies.

As described above, the present invention provides membrane electrodeassemblies incorporating an encapsulation process for electrodepositingpaint on a counter-electrode.

Generally speaking, the encapsulated membrane electrode assemblies ofthe invention, and used in Electro-coating systems will include membraneand electrode assembly including operational structures for the membraneelectrode cell encapsulated simultaneously to provide, a single mediumencasing, a sealed chamber between the counter-electrode, internal fluiddelivery and return system, and electrical input within saidelectro-deposition medium, wherein passage of electrical current betweensaid counter-electrode and said membrane electrode cell through saidliquid medium causing electro-deposition of said pigments and resins onto the said counter-electrode.

With reference now to FIG. 1, Disclosed is a membrane electrode assemblyof the present invention. Membrane electrode assembly includes exteriorcomponents, such as Non conductive barrier—2, Outer membrane support—7,Encapsulation guard—9, Anolyte inlet—10, Anolyte outlet—11, Powerlead—12.

With Reference to FIG. 1 and FIG. 2 together additional components ofthe assembly will be described. FIG. 2, A-A shows a partial cut-away ofthe assembly in order to reveal the layers of construction. Outermembrane support—7 provides the outermost layer, followed by the innermembrane support—6, followed by the membrane—5, and is separated fromthe electrode by the inner chamber formed during the encapsulationprocess. An inner membrane guard 8 formed of a suitable nonconductivematerial is placed in-between the membrane and electrode in the providedchannel. The anolyte channel—4 provides the distance required to createthe chamber between the electrode and the membrane. The electrode(anode)—3 and non conductive barrier—2 finish the operation layers ofthe invention. The encapsulation layer—1 is protected from impact by theencapsulation guard—9, which is of electrically non-conductive material.

With reference to FIG. 3 and FIG. 2 Showing the encapsulation processand the layers as described in FIG. 2. Referring now to FIG. 3, B-BEncapsulation material—1, anolyte channel 4, non-conductive barrierlayer—2, electrode (anode)—3, inner membrane guard—8, membrane—5, innermembrane support—6, outer membrane support—7. The assembly further showsthe Encapsulation guard—9 removed from the assembled invention.Referring now to FIG. 3, C-C, This view provides a look at theencapsulation of the components non conductive barrier—2, Electrode(anode)—3, Spacer and/or anolyte channel—4, membrane—5, inner membranesupport—6, outer membrane support—7, inner membrane guard—8, andencapsulation guard—9, while maintaining an opening for the internalfluid circulation provided by the anolyte channel—4. The same format isused with the anolyte outlet—11

while the invention has been illustrated and described in detail in thedrawings and description, the same is to be considered as notrestrictive and illustrative in character. Furthermore, only thepreferred embodiments have been shown and described and that all changesand modifications that come from the essence of the invention aredesired to be protected.

1. A system for electro-deposition of paint onto a counter electrode, inwhich the system incorporates an electro-deposition main tank containingelectrically conductive liquid medium consisting of pigment, resins,water, acids, or other; at least one membrane electrode assembly incontact with the above medium, said membrane and electrode assemblyincluding, but not limited to operational components for the membraneelectrode cell encapsulated simultaneously to provide a single mediumencasing, to provide a sealed chamber between the counter-electrode,internal fluid delivery and return system, and electrical input withinsaid electro-deposition medium, wherein passage of electrical currentbetween said counter-electrode and said membrane electrode cell throughsaid liquid medium causing electro-deposition of said pigments andresins on to the said counter-electrode, while attracting processedreleased ions to the chamber, relieving necessity of primary frames,first structures, or bonding components including membrane to saidstructures, while in turn reducing overall dimensions of the membraneelectrode assemblies.
 2. A system according to claim 1, wherein saidelectrode is a flat or c shaped electrode.
 3. A system according toclaim 1, wherein said membrane electrode structure, includingcomponents, electrical contact, and structures are encapsulated byresins simultaneously.
 4. A system according to claim 1, wherein thesaid membrane electrode structure including operational components, andstructures are encapsulated by extrusion simultaneously.
 5. A systemaccording to claim 1, wherein the said membrane electrode structureincluding components and structures are molded together in unison.
 6. Asystem according to claim 1, wherein the said membrane structureincluding components and structures is laminated in multi-layer bonding.7. A system according to claim 1, wherein after encapsulation process,the medium incorporated provides, the integrity of the encapsulatedcomponents, the enclosure, the sealing, and strength to a fullyencapsulated membrane electrode cell.
 8. A system according to claim 1,wherein after said encapsulation process the medium seals includedstructural components simultaneously.
 9. A system according to claim 1,wherein after said encapsulation process the medium provides, saidinternal space between the membrane and electrode for fluid passage. 10.A system according to claim 1, wherein within the encapsulation medium aprovision for at least one opening to direct fluid into the chamber. 11.A system according the claim 10, wherein the fluid leaves the channel inat least one port.
 12. A system according to clam 1, wherein theencapsulation process provides at least one opening for said fluid toexhaust the chamber.
 13. A system according to claim 1, wherein theencapsulation process provides at least one membrane support structure.14. A system according to claim 13, wherein membrane support structuresare electrically non conductive.
 15. Systems according to claim 13,wherein the membrane support structures are porous.
 16. A systemaccording to claim 1, wherein encapsulation process provides electricalinsulation of the chamber using a barrier sheet of non-conductivematerial.
 17. A system according to claim 1, wherein an edge-guard canbe applied around the perimeter of the encapsulation to protect it fromimpact.
 18. A system according to claim 1, wherein the said membrane isan ion-selective membrane.
 19. A system according to claim 1, whereinthe membrane is non-ion selective.
 20. A system according to claim 1,wherein the said electrode is formed from conductive material.
 21. Asystem according to claim 1, wherein the assembly process can provide anultra slim profile of an electrode membrane cell.